Sound drift using Z1, Aspect and MOTU Audiodesk at DVinfo.net

John Kahoun · November 2nd, 2007, 03:21 PM

Have several long scenes (30 minutes) recorded to 50i with the Z1, captured with HDlink 4.3 (with deinterlacing), and trying to sync up with sound recorded using a MOTU Traveler (with Audiodesk software) to an iBook (48mhz, 16 bit). Video and audio drift progressively where, by twenty five minutes, the video one second ahead of the sound.

No idea where the problem is, but any ideas would be appreciated.

BTW, PP CS3 says the video is 20 fps in the properties window, but shows 25 frames on the timeline. Upgrading from Aspect 4 to the trial version of Aspect 5 had no effect on this or the above problem. Haven't tried recapturing with HDlink bundled with Aspect 5 yet. might this help?

Thanks

Mike McCarthy · November 3rd, 2007, 12:47 AM

The 20fps reporting for PAL footage is supposed to be fixed by the Premiere 3.1 update. As far as the sync goes, try adjusting the audio speed to 100.1% o 99.9% Sometimes it will be 1/1000 off due to the difference between 29.97 and 30fps (.03fps different) The are 48,048hz and 47,952hz settings on certain devices to compensate for that. (+/- 48hz, 1/1000 of 48khz) See the audio export options in AE for example. Not sure how that fits into the PAL world, but your audio system might be trying to compensate for that NTSC reality.

David Newman · November 3rd, 2007, 09:54 AM

Make sure you don't have 3-2 pulldown selected for 50i capture, as that will turn 25fps to 20fps.

John Kahoun · November 7th, 2007, 10:14 AM

Thanks for the help guys

turns out the sound's off 0.06%, so i speed it up to 100.05% inside PP and synchs up fine. guess that's the risk you take with 30 minute takes. actually one of the Z1's is off (sound and video) by the same amount (shot with 3 cameras) - don't know what's up with that.

you were indeed right, David. Since i'm capturing 50i, didn't pay attention to that setting on HDlink. Thought the 3-2 pulldown was exclusive to 60i, etc. Anyway, turned it off on capture and (with deinterlacing) have all the tapes uploadedin 25p.

btw, the hdlink in aspect 5 is much more stable than 4.3.

November 2nd, 2007, 03:21 PM	#1
John Kahoun New Boot Join Date: Oct 2006 Location: buenos aires, argentina Posts: 7	Sound drift using Z1, Aspect and MOTU Audiodesk Have several long scenes (30 minutes) recorded to 50i with the Z1, captured with HDlink 4.3 (with deinterlacing), and trying to sync up with sound recorded using a MOTU Traveler (with Audiodesk software) to an iBook (48mhz, 16 bit). Video and audio drift progressively where, by twenty five minutes, the video one second ahead of the sound. No idea where the problem is, but any ideas would be appreciated. BTW, PP CS3 says the video is 20 fps in the properties window, but shows 25 frames on the timeline. Upgrading from Aspect 4 to the trial version of Aspect 5 had no effect on this or the above problem. Haven't tried recapturing with HDlink bundled with Aspect 5 yet. might this help? Thanks

November 3rd, 2007, 12:47 AM	#2
Mike McCarthy Major Player Join Date: Oct 2007 Location: Northern California Posts: 517	The 20fps reporting for PAL footage is supposed to be fixed by the Premiere 3.1 update. As far as the sync goes, try adjusting the audio speed to 100.1% o 99.9% Sometimes it will be 1/1000 off due to the difference between 29.97 and 30fps (.03fps different) The are 48,048hz and 47,952hz settings on certain devices to compensate for that. (+/- 48hz, 1/1000 of 48khz) See the audio export options in AE for example. Not sure how that fits into the PAL world, but your audio system might be trying to compensate for that NTSC reality. __________________ For more information on these topics, check out my tech website at www.hd4pc.com

November 3rd, 2007, 09:54 AM	#3
David Newman CTO, CineForm Inc. Join Date: Jul 2003 Location: Cardiff-by-the-Sea, California Posts: 8,095	Make sure you don't have 3-2 pulldown selected for 50i capture, as that will turn 25fps to 20fps. __________________ David Newman -- web: www.gopro.com blog: cineform.blogspot.com -- twitter: twitter.com/David_Newman

November 7th, 2007, 10:14 AM	#4
John Kahoun New Boot Join Date: Oct 2006 Location: buenos aires, argentina Posts: 7	Thanks for the help guys turns out the sound's off 0.06%, so i speed it up to 100.05% inside PP and synchs up fine. guess that's the risk you take with 30 minute takes. actually one of the Z1's is off (sound and video) by the same amount (shot with 3 cameras) - don't know what's up with that. you were indeed right, David. Since i'm capturing 50i, didn't pay attention to that setting on HDlink. Thought the 3-2 pulldown was exclusive to 60i, etc. Anyway, turned it off on capture and (with deinterlacing) have all the tapes uploadedin 25p. btw, the hdlink in aspect 5 is much more stable than 4.3.